The present invention relates to medical devices and methods, and more particularly to medical devices and methods used while a patient is anesthetized.
Continuous monitoring of exhaled CO2, referred to as capnography, is the conventional standard of care for monitoring a patient's ventilation during operating room procedures. Capnography is also often used during non-intubated procedures that use moderate or deep sedation. A popular means for capnography is the well-known nasal cannula, such as disclosed in U.S. Pat. Nos. 5,335,656 and 6,439,234, which uses one nasal tube to supply oxygen to the sedated patient and another nasal tube to draw end-tidal CO2 for monitoring. A conventional Nasal Cannula (Adult) Salter Style® Ref 4707F from Salter Labs is packaged with several feet of side-by-side oxygen supply tubing and sampling lumen tubing, which terminates at individual, free tubes that are connected to opposing sides of the nasal cannula body.
Typically, the tubes connected to opposing ends of the nasal cannula are looped over the patient's ears, and then the tubes merge into a side-by-side configuration that extends to the oxygen supply and capnography system.
Under certain conditions, the sedated patient may receive insufficient oxygen through the nasal passages, such as when the nasal passages are blocked. An anesthetist might then place the nasal cannula in the patients mouth, such as through a portion of a bite block (if present), and increase the oxygen flow.